A team from the University of Alaska Museum of the North has succeeded in excavating the fossil of a rare, ancient marine reptile from rock that's usually covered by the tide.

Eugene Primaky, working for the USDA Forest Service Heritage Program out of Petersburg, spotted what he thought might be the bones of a fish or a branch while looking over an intertidal outcropping near Kake in Southeast Alaska in May. He gave it a kick. It didn't move.

Photos were sent to the museum's earth sciences curator, Patrick Druckenmiller, who quickly determined that it was the back end of a little-known sea-going reptile from the age of the dinosaurs called a thalattosaur, Greek for "sea lizard."

The fossil was found in a formation estimated to be 220 million years old. "Based on the age of the rocks and what I could see in the picture, I was 99 percent sure that's what it was," Druckenmiller said.

Druckenmiller and a colleague, Kevin May, traveled to the site in mid-June to collect the specimen. The site was exposed only during extreme low tides at certain times of year. The team faced a two-day window in which they had just four hours each day to remove the fossil. The next chance to do so wouldn't come until October.

Rock saws were used to hack into the layers surrounding the fossil. The workers managed to complete the excavation just five minutes before the site went underwater on the first day. But Druckenmiller spotted yet more bone penetrating the rock. A larger section was removed on the second day in hopes that it would contain the rest of the skeleton.

The two slabs, weighing 500 pounds, were shipped to Fairbanks. There, at the museum's fossil preparation lab at the museum, rock will be slowly chipped away to expose as much of the complete skeleton as still exists. The process will take several months.